For backroom staff and other "hidden" attributes which can not be found with FMSE, They are found within the "database" editor OR in some cases the "In-Game" editor.
Some staff members such as board members may not have editable attributes with the in-game editor. It's been a while since I have fiddled around with it. I know for sure there is editable attributes with the database editor - the issue with that though is that you would need to start a new save, unlike the "In-Game" editor.
If you have the "In-Game" editor, I would give it a shot through that.